Commit 01ab1039 authored by Michael Trimarchi's avatar Michael Trimarchi Committed by Paul Mundt
Browse files

sh: Fix up DSP context save/restore. 



There were a number of issues with the DSP context save/restore code,
mostly left-over relics from when it was introduced on SH3-DSP with
little follow-up testing, resulting in things like task_pt_dspregs()
referencing incorrect state on the stack.

This follows the MIPS convention of tracking the DSP state in the
thread_struct and handling the state save/restore in switch_to() and
finish_arch_switch() respectively. The regset interface is also updated,
which allows us to finally be rid of task_pt_dspregs() and the special
cased task_pt_regs().

Signed-off-by: default avatarMichael Trimarchi <michael@evidence.eu.com>
Signed-off-by: default avatarPaul Mundt <lethal@linux-sh.org>
parent a27873cd

arch/sh/include/asm/processor_32.h

+13 −0
Original line number Diff line number Diff line
@@ -57,6 +57,14 @@ asmlinkage void __init sh_cpu_init(void); 
#define SR_IMASK	0x000000f0

#define SR_FD		0x00008000



/*

 * DSP structure and data

 */

struct sh_dsp_struct {

	unsigned long dsp_regs[14];

	long status;

};



/*

 * FPU structure and data

 */
@@ -96,6 +104,11 @@ struct thread_struct { 


	/* floating point info */

	union sh_fpu_union fpu;



#ifdef CONFIG_SH_DSP

	/* Dsp status information */

	struct sh_dsp_struct dsp_status;

#endif

};



/* Count of active tasks with UBC settings */

arch/sh/include/asm/ptrace.h

+0 −8
Original line number Diff line number Diff line
@@ -119,16 +119,8 @@ struct task_struct; 
extern void user_enable_single_step(struct task_struct *);

extern void user_disable_single_step(struct task_struct *);



#ifdef CONFIG_SH_DSP

#define task_pt_regs(task) \

	((struct pt_regs *) (task_stack_page(task) + THREAD_SIZE \

		 - sizeof(struct pt_dspregs)) - 1)

#define task_pt_dspregs(task) \

	((struct pt_dspregs *) (task_stack_page(task) + THREAD_SIZE) - 1)

#else

#define task_pt_regs(task) \

	((struct pt_regs *) (task_stack_page(task) + THREAD_SIZE) - 1)

#endif



static inline unsigned long profile_pc(struct pt_regs *regs)

{

arch/sh/include/asm/system_32.h

+123 −47
Original line number Diff line number Diff line
@@ -3,6 +3,66 @@ 


#include <linux/types.h>



#ifdef CONFIG_SH_DSP



#define is_dsp_enabled(tsk)						\

	(!!(tsk->thread.dsp_status.status & SR_DSP))



#define __restore_dsp(tsk)						\

do {									\

	register u32 *__ts2 __asm__ ("r2") =				\

			(u32 *)&tsk->thread.dsp_status;			\

	__asm__ __volatile__ (						\

		".balign 4\n\t"						\

		"movs.l	@r2+, a1\n\t"					\

		"movs.l	@r2+, a0g\n\t"					\

		"movs.l	@r2+, a1g\n\t"					\

		"movs.l	@r2+, m0\n\t"					\

		"movs.l	@r2+, m1\n\t"					\

		"movs.l	@r2+, a0\n\t"					\

		"movs.l	@r2+, x0\n\t"					\

		"movs.l	@r2+, x1\n\t"					\

		"movs.l	@r2+, y0\n\t"					\

		"movs.l	@r2+, y1\n\t"					\

		"lds.l	@r2+, dsr\n\t"					\

		"ldc.l	@r2+, rs\n\t"					\

		"ldc.l	@r2+, re\n\t"					\

		"ldc.l	@r2+, mod\n\t"					\

		: : "r" (__ts2));					\

} while (0)





#define __save_dsp(tsk)							\

do {									\

	register u32 *__ts2 __asm__ ("r2") =				\

			(u32 *)&tsk->thread.dsp_status + 14;		\

									\

	__asm__ __volatile__ (						\

		".balign 4\n\t"						\

		"stc.l	mod, @-r2\n\t"				\

		"stc.l	re, @-r2\n\t"					\

		"stc.l	rs, @-r2\n\t"					\

		"sts.l	dsr, @-r2\n\t"				\

		"sts.l	y1, @-r2\n\t"					\

		"sts.l	y0, @-r2\n\t"					\

		"sts.l	x1, @-r2\n\t"					\

		"sts.l	x0, @-r2\n\t"					\

		"sts.l	a0, @-r2\n\t"					\

		".word	0xf653		! movs.l	a1, @-r2\n\t"	\

		".word	0xf6f3		! movs.l	a0g, @-r2\n\t"	\

		".word	0xf6d3		! movs.l	a1g, @-r2\n\t"	\

		".word	0xf6c3		! movs.l        m0, @-r2\n\t"	\

		".word	0xf6e3		! movs.l        m1, @-r2\n\t"	\

		: : "r" (__ts2));					\

} while (0)



#else



#define is_dsp_enabled(tsk)	(0)

#define __save_dsp(tsk)		do { } while (0)

#define __restore_dsp(tsk)	do { } while (0)

#endif



struct task_struct *__switch_to(struct task_struct *prev,

				struct task_struct *next);
@@ -11,14 +71,24 @@ struct task_struct *__switch_to(struct task_struct *prev, 
 */

#define switch_to(prev, next, last)				\

do {								\

	register u32 *__ts1 __asm__ ("r1") = (u32 *)&prev->thread.sp;	\

	register u32 *__ts2 __asm__ ("r2") = (u32 *)&prev->thread.pc;	\

	register u32 *__ts4 __asm__ ("r4") = (u32 *)prev;		\

	register u32 *__ts5 __asm__ ("r5") = (u32 *)next;		\

	register u32 *__ts6 __asm__ ("r6") = (u32 *)&next->thread.sp;	\

	register u32 __ts7 __asm__ ("r7") = next->thread.pc;		\

	register u32 *__ts1 __asm__ ("r1");			\

	register u32 *__ts2 __asm__ ("r2");			\

	register u32 *__ts4 __asm__ ("r4");			\

	register u32 *__ts5 __asm__ ("r5");			\

	register u32 *__ts6 __asm__ ("r6");			\

	register u32 __ts7 __asm__ ("r7");			\

	struct task_struct *__last;				\

								\

	if (is_dsp_enabled(prev))				\

		__save_dsp(prev);				\

								\

	__ts1 = (u32 *)&prev->thread.sp;			\

	__ts2 = (u32 *)&prev->thread.pc;			\

	__ts4 = (u32 *)prev;					\

	__ts5 = (u32 *)next;					\

	__ts6 = (u32 *)&next->thread.sp;			\

	__ts7 = next->thread.pc;				\

								\

	__asm__ __volatile__ (					\

		".balign 4\n\t"					\

		"stc.l	gbr, @-r15\n\t"				\
@@ -58,6 +128,12 @@ do { \ 
	last = __last;						\

} while (0)



#define finish_arch_switch(prev)				\

do {								\

	if (is_dsp_enabled(prev))				\

		__restore_dsp(prev);				\

} while (0)



#define __uses_jump_to_uncached \

	noinline __attribute__ ((__section__ (".uncached.text")))

arch/sh/kernel/cpu/sh3/entry.S

+6 −79
Original line number Diff line number Diff line
@@ -254,40 +254,6 @@ restore_all: 


	lds	k2, pr			! restore pr

	!

#ifdef CONFIG_SH_DSP

	mov.l	@r15+, k0		! DSP mode marker

	mov.l	5f, k1

	cmp/eq	k0, k1			! Do we have a DSP stack frame?

	bf	skip_restore



	stc	sr, k0			! Enable CPU DSP mode

	or	k1, k0			! (within kernel it may be disabled)

	ldc	k0, sr

	mov	r2, k0			! Backup r2



	! Restore DSP registers from stack

	mov	r15, r2

	movs.l	@r2+, a1

	movs.l	@r2+, a0g

	movs.l	@r2+, a1g

	movs.l	@r2+, m0

	movs.l	@r2+, m1

	mov	r2, r15



	lds.l	@r15+, a0

	lds.l	@r15+, x0

	lds.l	@r15+, x1

	lds.l	@r15+, y0

	lds.l	@r15+, y1

	lds.l	@r15+, dsr

	ldc.l	@r15+, rs

	ldc.l	@r15+, re

	ldc.l	@r15+, mod



	mov	k0, r2			! Restore r2

skip_restore:

#endif

	!

	! Calculate new SR value

	mov	k3, k2			! original SR value

	mov	#0xf0, k1
@@ -358,7 +324,7 @@ general_exception: 
	add	k0, k4

0:

	! Setup stack and save DSP context (k0 contains original r15 on return)

	bsr	prepare_stack_save_dsp

	bsr	prepare_stack

	 nop



	! Save registers / Switch to bank 0
@@ -374,15 +340,14 @@ general_exception: 
1:	.long	EXPEVT

#endif



! prepare_stack_save_dsp()

! prepare_stack()

! - roll back gRB

! - switch to kernel stack

! - save DSP

! k0 returns original sp (after roll back)

! k1 trashed

! k2 trashed



prepare_stack_save_dsp:

prepare_stack:

#ifdef CONFIG_GUSA

	! Check for roll back gRB (User and Kernel)

	mov	r15, k0
@@ -416,47 +381,9 @@ prepare_stack_save_dsp: 
	mov	k1, r15		! change to kernel stack

	!

1:

#ifdef CONFIG_SH_DSP

	! Save DSP context if needed

	stc	sr, k1

	mov	#0x10, k2

	shll8   k2			! DSP=1 (0x00001000)

	tst	k2, k1			! Check if in DSP mode (passed in k2)

	bt/s	skip_save

	 mov	#0, k1			! Set marker for no stack frame



	mov	k2, k1			! Save has-frame marker



	! Save DSP registers on stack

	stc.l	mod, @-r15

	stc.l	re, @-r15

	stc.l	rs, @-r15

	sts.l	dsr, @-r15

	sts.l	y1, @-r15

	sts.l	y0, @-r15

	sts.l	x1, @-r15

	sts.l	x0, @-r15

	sts.l	a0, @-r15



	! GAS is broken, does not generate correct "movs.l Ds,@-As" instr.



	! FIXME: Make sure that this is still the case with newer toolchains,

	! as we're not at all interested in supporting ancient toolchains at

	! this point. -- PFM.



	mov	r15, k2

	.word	0xf653			! movs.l	a1, @-r2

	.word	0xf6f3			! movs.l	a0g, @-r2

	.word	0xf6d3			! movs.l	a1g, @-r2

	.word	0xf6c3			! movs.l	m0, @-r2

	.word	0xf6e3			! movs.l	m1, @-r2

	mov	k2, r15



skip_save:

	mov.l	k1, @-r15		! Push DSP mode marker onto stack

#endif

	rts

	 nop



!

! 0x400: Instruction and Data TLB miss exception vector

!
@@ -468,7 +395,7 @@ handle_exception: 
	mova	exception_data, k0



	! Setup stack and save DSP context (k0 contains original r15 on return)

	bsr	prepare_stack_save_dsp

	bsr	prepare_stack

	 PREF(k0)



	! Save registers / Switch to bank 0
@@ -572,7 +499,7 @@ ENTRY(handle_interrupt) 
	mova	exception_data, k0



	! Setup stack and save DSP context (k0 contains original r15 on return)

	bsr	prepare_stack_save_dsp

	bsr	prepare_stack

	 PREF(k0)



	! Save registers / Switch to bank 0

arch/sh/kernel/process_32.c

+13 −1
Original line number Diff line number Diff line
@@ -176,14 +176,26 @@ int copy_thread(int nr, unsigned long clone_flags, unsigned long usp, 
{

	struct thread_info *ti = task_thread_info(p);

	struct pt_regs *childregs;

#if defined(CONFIG_SH_FPU)

#if defined(CONFIG_SH_FPU) || defined(CONFIG_SH_DSP)

	struct task_struct *tsk = current;

#endif



#if defined(CONFIG_SH_FPU)

	unlazy_fpu(tsk, regs);

	p->thread.fpu = tsk->thread.fpu;

	copy_to_stopped_child_used_math(p);

#endif



#if defined(CONFIG_SH_DSP)

	if (is_dsp_enabled(tsk)) {

		/* We can use the __save_dsp or just copy the struct:

		 * __save_dsp(p);

		 * p->thread.dsp_status.status |= SR_DSP

		 */

		p->thread.dsp_status = tsk->thread.dsp_status;

	}

#endif



	childregs = task_pt_regs(p);

	*childregs = *regs;

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